Means for reducing reflection losses in duplex circuits.



T. SHAW. MEANS FOR REDUCING REFLECTION LOSSES IN DUPLEX CIRCUITS.

APPLICATION FILED FEB. 28, 1913 M in assay:

, v z Th 0m (16 {5 h aw I '6 7 5/ Jimu In renter Patented Apr. 14, 1914.

- i ,eseess;

bf mie line in ins 'rsoims siiew, e1? meezeiisecs, ii'sw misses"; eesitsiiieie,

i e GGEEGM'EIO'M 6.71? .imw oms we essziseeeeu cease re,

are emizi xces emesimi'ie Y Y lemme me sshsems m eiimmes.

To kzlljuliomfi maywnr'emz Y i ,Be it imown thsfc E, Therese eisi th'e'United States, residing {is Heck e1is:iek, in {he (hunt-y i 'EQYg'EH ziaiici; State of New Jersey; have iiiveiiteeleevisin Improvements iii iiieshsffor -fi-eiueing Reheaivei' 'whisii T0 i'iei 'i'ezise the trans-(ms by reflect-ion 212'}: t'hgjimetie lines of ciifierent impedance 2i 1 these to step 1}? or down. the exisemay be that (if the other; this refieetion reducing means being most efieetive w hn the impedance "ratio of the transformer e51 sis the msio nfthefiiiipedsnee of the iines.

4 .The present invention has ior its Object means 0f this Chametev,

' respect reflection rec aiming it being espetziriiliy teiephone ei'gemts, as e.- ihe side or physical sixcuitsof which it is-cemphsed.

Pieeu'nselhf theigreaiiex efiieieziey eve? she both with of the cype certain impi-ovenients in nppiicahie in duplex sep'arzite w nding; transinx'mer,

re-copper and ron hasses of device commonly known'assn eu tot'm'nsformer, in hit-h mi the circuits, this Lion is more. specifically the windings are conflueiively'connected, and because of its-main tens-hoe of the'ihrect. 'condnciive coi'itimiity device is useful in the present connection,

concerned.

In the-accompanying drawings, in which similar referei ce characters designate [like parts thi' on-ghmiiz,Figure 1 shews ciiag gsm 1r'iaticii11ydiipiex circuits-having my ii -fem Lion. applied thereto; and Fig; a diagram are; portions of cuit furnished by in parallel, together w th the isuai terminal in gi'eater dehiil of an mitotmnsrofmer iihiscrating-an embedimenbni iheinventien.

Referring to Fi v10f the drawings, thei e duplex telephone fireflies,- these comprising in the present instance-the physical or side (iiClli'LS, eache hsistihg 0T: conduetorsjifi and L", and the phantom ciz-a the eohchicioi's'ifi and If,

arrangements. In describing this invention it will. be assumed that zit less; one of the side CiYGUi ZS is media up 'oisuccessive lines or line sections S and S- Of (iiffereiit imedence g' presenting iess impedance than $1 at the junction of which reiieetioiilosses teni to occur. These portions 8 and 0i s geeificstios sf F nest the eireiiii s may sp edway.-

nflame section flows and serieswindings, the-letter csi'rying this The resultantci vrens'iii. ihel is the dif'fei-enee between,

.being-eonfineci to said and with it my inv'eib fmeei ees Apr; M, ism meilfiei seems:

pe iihm 0% greater length, or

.msyhe'mereiy sections of a; cifemit perm- I nmsly cemieesedybiithemafier when the seam line seciiens is iisedi it is to he un efsismii w slppiy to either srramgemnii. --ss 'ihe gvmehmn 0% sections S said 13 an iz'ieiuetive repeating device, prefeisbiyan eiisoti'ziiisformei' E eenwntim isiiy re ere sensed in Such e,- tmnsfemhee appears m'eeeh o the side circuits, though bifit one will be srticularlydescribed. 1thss tivo sets of wind ingstsnd 2?, 23- whichmay conveniently be ciiiied the brige we series windings ire- The winding tis; bridged across l and more eompieteiyin Fig.

cmsaisi: of index 1 jeinedm gives the junction. 0% the two cimulfisections,

while the series winciiiigs exe eo'nnecteeit0 the extremities of the bridge in each. (if the conductors L :mdLL

sectimi S 'Theei rifentin the high imicm'i'ent niy. bridge winding that in the low and high impedance sections, the current of the low bridge windin $0 anew common battery signaiisg, and

"5501" ofi-hei" pi zcposes m which a meta-Hie bridge of the line 1s ob ectiembie, thecsntinuity of the winding- 5 is broken by s, comienser, or

iii the high impedance impecian'ce seetlen through the bricige y pieifeeebly a balanced. system of cemiensers C, C, from between which any 'd esrmdeone nectien, as a, may he lech This conductor 0. is here shown fiS jnined to an the bridge Winding u of aiisoti'snsfermer U, having series windings u? in 'comhict'brs of both siiie circuits. Thistmns forms}: U, 'wvhichbelongs to the phantom (ZiKfGlliifi, "wiii not be further described, its de tails playing no ticm. e 1

' One-of the principal aims in w icefiect-isn reriucing (Revise sppiiefi t0 dupiex circiiifis is to amiss the prouction sf its fullefieeh upon the circuit to which is is directly relates;- whiie minimizin the effect upon the asse sister} circuiis hat? is, in the'pi-esensim extremity eieach 0f the;

pair; in the present iiivew stance she impedance 015 the bridge wimiing 4 a shouhi eoersspond as closely as pessihle he the im 7 ciszice (If the; sectieh. S o the. hwsi j cs3. circuit, semi the impedance 0%- the emiige 7 But: for the tions may be divided into two cause of the symmetrical arrangenlent of the" since the Luiiform distribht ion of the windof the transformer upon the phantom circuit will amount only to theintroducti on or the practically negligible direct currentresistance of. the transformer; windings in parallel groups. very complete impedance balance is ob-- gether in series to that of the section S the efi'ect phantom circuit which the uit a component, the impl edphysical c'irc I shop 1d lie 1 as ances of the trmlsfoi'nier nearlyas possible negligible. the sametime the transformer should be so' organized as n'ot -to introduce electromagnetic or elec- 'trostatic crosstalk between the, side and phantom circuits, the'operating-fcurrent in both of which traverse: it. These features are provided by the present-invention, The preferred arrangement of the eleinentsggofthe transformer isillustratedin detailfin Fig. 2. The windings are best identified in this figure by numbers applied to their terminals; these numbers also appearing in'thei'r proper relation in Fig. l. (A core A having'a closed; magnetic circuit issho'ix this being-prefer-'-' ablyof toroidal form. Extending about the: entire core is" the bridge winding 25 and the.=

series windings 't 'f'and TheJwlnding it 17's:

tween the side circuit and the phantom.

his results from the equality of the sections-- in the bridge and series windings, respectively, and the symmetrical distribution of .tltescsections. The twisting of the bridge "sect-ions together gives [perfectmutual sym-' 'metry with regard to the series windings;

othing would be nterleaving [the latter ttffined between them wlthoutth'e introducgtioin of transmission losses throu h shunt. foapacities, which are greater in twisted con-' divided into sections. between which the con-i ducfors- A's toielectrostatic crosstalk through" densers areh'inserted, these sections having. direct admittances,

the terminals ol -2 and 56. T and balance oneanot winding i iii conductor L has the terminals; 1 illustrated, exceptbetween the bridge wind- 3-4, and the series winding 6 in conductor ing and the core, and between the outer lay- L has terminals 78. Each series winding sections, allithe sechavingl the same number of turns. EitherK/t'hebridge or series windings prefer- ,ably'co'nsist oit' a twisted-pair of conductors. In the present instance the bridge winding is thus 'arr anged, and it is situated next to tlon. I v the core. Each series winding also emliy' properly] proportioning the various braces the entire core with its sections upon' transtormer windings an impedance ratio opposite halves, the sections of the same may be obtained adapting it to an particuwinding beingp'at difl'erent distances from. lar valu'es'of circui said core. In other words,- each series winding has inner layers upon one portion of the core next, the bridge winding, and outer 1 layers alpon'the opposite portion, I As thesebefore described, havuigthe ratio of 3 to 1. windings are distributed and'j connected, they The bridgewinding sections 1-2 and 5 -6 are i'n series with respect tow" ii rent in the may each have 635 turnsof conductor with side circuit with ,their mutualginductance a direct current-resistanceo-f 5 ohms, and jliding the self .inrlnctances; and "the imped the series windings and 7-8 each 465 ance ratio, whFelt-controls the-"reflection returns with a'direct current resistance of '5 ducing efficiency-of the devide, will be the ohms. ratio of the impedance of *{w i ndings 4 3, introduced, for 21, 65 and 8-7, in series aidingto that and neglecting the con of the bridgewinding 'sectio1is 2:4, .6-,-5. ance'ot 190 ohms and 0.8 hem? a b d similarly related The effect Qt the transimpedance of 342 ohms and 1.49 ienrysya'nd former on the phantont cireuitfwill'be to in- .a mutual impedance of 244 ohms elude therein. il'npeda'ne'e'i'e'qhal'i-to' the series hcnryst' For the phantom circuit. windings l-3, 78 in parallel with their mutual inductance opposing their.Iself indlictances, plus the bridge winding sections 2--1 also inparallel-opposing. .Be-o

.ers of the series windings, between which there will .be differences of potential.v ,This,' however. does n ot'cause serious dist theme and maybe less 0b reducing efli ciency. I will give the a proximate data for a transformer such as erem-'- a f-re uency of 800 cycles ensers', series 1m edthere will and 0.0005 henr-y each..

the phantom circuit coil situated at the junction of the combination of'this coil and the sidecircuit' coil located between theline sections is not lltIO'lll clainuxl, as the some forms 'ject matter of and claimed in my copend-- ing a 'i' 'iliration Serial No. 751,288, filed l cbruary 28,1913. The transformer con- 1 struction II, also shown.- herein and not windings, the -mutual inductance between one portion of the blltlge wji'ldlllg and. the series windingsjwlll balance that between the other portion and the-series. windings; andings about the entire'core avoids any stantial leakagcnnpedance between them,

he series and l'u'idge impedanceof'3' .ohms

ta1ned,-in this transformer with a resultant freedom from electromagnetic crosstalk bcgained in this direction 1 by" also twisting the series windings, and by I ood balanceis ob these are symmetrical her in the organization ers. of said bridge winding and the inner lay-' on jectionable than further complication'i'n the transformer. coristrucloo v t'sect onimjpe mice, and therefore leading to a maximum reflection IM' For each side circuit-there will be and 1.085.. I

The matter disclosed herein relating to a phantom sections and 'to' the,

the .sub-

- connection with said win'd'i b the resultant another winding upon the at d sectioia, tug of a twist entire core. I, i

14.. The combination with line sections, of atransforna-r iiH;ll( i at he junction of the sectionsand inning a core. windings in series upon saidyoretrarerwd by eurrentflin one set-lien and another winding haying conductive count-(that with said windings. traversed by the resultant current of HSSIP td pair extending about the eiat'ed sections and ('OIISWliHg of a twisted pair-extending aboutthefent ire core.

13. The combination with hue a transformer at the unction of the sections tings in 't-ties upon said'eore travpath. with 'g'tlll'tlltin one section, another ersed by one of said windingscbnsisb having windings, traversed by the set'tions,'oi'

sections and having a.

"upon said core in isted pair extending the series windingsbei rd associated sections p'osite halves 01' the core. 1 18. The combination with line sections, of

f a transformer situated at the junction of the 'llltiitlg llptltt said core haying conductive ngs and traversed current of. associated seetions, one-of said the entire core and the ot on'diii'erent. portions of the ferent distances tht-i'efroni.- I

16. The combinationwith line sections, of a transformer at the junction the core traversed by current on one core having conductive connection with said wind traversed by the resultantcurrent eiat'ed sections, one of said windings extending about the entire of each winding'on diiferent' portions of the core.

her' windings bein core and at (11 having: a core furnishing a elosed'niagnetie f windings extending about o'f-the sections 5 and having a core, windings in seriesupon I section,

ings and of asso- ,core and the other 1 windings being in sections \Vith'tihGSCGtiOIlS other windings being sections of each winding on dit i'erent porseetiong and having" a core furnishing 'a' closed magnetic path,

core in series traversed by current in one of the sections, oth'erwindings upon the core having condueti ve connection with said tirst-i'iained windingstraversed by the result'ant currentof associated sections, one of said windings consisting of a twisted-pair extending about the entire core and the in sections with the tin; of the core, the sections of different windings being at di-tYerent distances from the c0re.-

In testimony whereof, I have signed'iny name to thi specification in the presence. of

two subscribing witnesses this eighteenth day of l ebruary, 1,913."

- THOMAS SI-IAV Witnesses: I

ELAM Miiiiiicit, LLOYD, I lsrnxscnnan.

' .\'indings in series windings upon the ng in sections on op- 

